Cup-seal non-return valve

ABSTRACT

In order to protect a cup-seal non-return valve (1) against permanent deformation, it is suggested to provide radial supporting walls (15) between the cylindrical inner wall (10)* (*translator&#39;s note: the correct reference numeral is `14`) and the sealing lip (13). Preferably, three supporting walls (15), roughly 1 mm thick, are provided because both the natural stability and the valve function are safeguarded this way.

The present invention is based on a cup-seal non-return valve accordingto the preamble of the main claim.

Usually such cup-seal non-return valves abut with their inner wallsealingly in an annular groove of a piston which they seal with theirsealing lip in relation to an encompassing bore wall. Once pressure isbuilt up from the open end of the V-profile, the sealing lip pressestighter against the bore wall. In case pressure build-up is effectedfrom the closed end of the V-profile, the sealing lip lifts from thebore wall, bears against the inner wall of the cup-seal non-return valveand establishes a pressure fluid passage in this direction. Thisrepresents a low-cost space-saving alternative compared tospherical-seat-type non-return valves. However, especially in designswith a very low opening pressure, it may happen that the sealing lipremains stuck on the inner wall, collapses under the effect of pressureor is deformed permanently in any other way.

Therefore, it is an object of the present invention to provide acup-seal non-return valve of the above kind which functions in a durableand reliable manner.

This object is achieved by the features of the characterizing portion ofthe main claim. Further, the radial supporting walls permit the sealinglip to at least partly lift from the bore wall, yet they prevent that itsticks to the inner wall and exert a small but sufficient restoringforce on the sealing lip. Collapsing of the sealing lip is successfullyprevented as well.

Three supporting walls spread over the periphery prove to beparticularly favourable. On the one hand, their distances are largeenough to keep the initial pressure of the cup-seal non-return valvelow. On the other hand, they are small enough to have a stabilizingeffect over the entire periphery.

Especially as regards pressure-reducing valves which e.g. operate asbrake force control valves and in which cup-seal non-return valves ofthe above type are frequently used in order to ensure a quick reductionof the rear-wheel braking pressure when braking is terminated, cup-sealnon-return valves according to the present invention contribute toenhancing the durability to a major extent.

An exact explanation of the idea of this invention will follow by way ofthe description of two illustrations.

In the drawing,

FIG. 1 is a segment of a pressure-reducing valve in which an inventivecup-seal non-return valve is mounted,

FIG. 2 is a top view of a cup-seal non-return valve according to thepresent invention.

In FIG. 1 the cup-seal non-return valve 1 is fitted into thepressure-reducing valve 2 between the inlet chamber 3 and the outletchamber 4. It embraces in an annular groove the stepped control piston5, the open end of the cup-seal non-return valve 1 facing the inletchamber 3, while the closed end thereof faces the outlet chamber 4.

The control piston 5 is guided in the bore 6, the large effectivecontrol piston radius R being disposed between inlet chamber and outletchamber 3 and 4, respectively, while the small effective control pistonradius r projects in a sealed manner through the stationary sleeve 7into a chamber devoid of pressure fluid.

When the pressure-reducing valve is unpressurized, the control piston 5is in its initial position in abutment on the front wall 8 confining thebore 6 so that the tappet 9 lifts the valve closure member 10 from thevalve seat 11 as is shown in the upper half of the illustration.

When the pressure rises from the inlet chamber 3, the control piston 5starts to move in opposition to the compression spring 12 in thepresence of a change-over pressure which is determined by the differenceof the pressurized surfaces, on the one hand, and the spring rate of thecompression spring 12, on the other hand. The valve closure member 10moves to sealingly rest on the valve seat 11, as is shown in the bottomhalf of the illustration. With the pressure continuing to rise in theinlet chamber 3, the pressure rise in the outlet chamber 4 is reducedproportionally.

When finally pressure is decreased in the inlet chamber 3, the cup-sealnon-return valve 1 establishes an additional pressure fluid passage fromthe outlet chamber 4 to the inlet chamber 3 by lifting the sealing lip13 from the wall of the bore 6. This is important because the controlpiston cannot return to its basic position as long as the force ofpressurization on the outlet side exceeds the force of the compressionspring 12. That is to say, the discharge of pressure fluid takes placethrough the valve 10/11, which acts as a non-return valve in thisposition of the control piston, and through the cup-seal non-returnvalve 1 so that the pressure in the outlet chamber 4 quickly adapts tothat in the inlet chamber 3 and the control piston moves into itsinitial position again.

The cup-seal non-return valve 1 itself has a cylindrical inner wall 14which over its surface is in constant sealing abutment on the controlpiston 5.

Connected with this wall at an axial end is the sealing lip 13 whichtransversely projects outwardly so that a V-shaped profile results. Atthe open end of the V-profile the cylindrical inner wall 14 projectsaxially beyond the sealing lip 13. In the unpressurized condition thesealing lip 13 fits closely to the wall of the bore 6 encompassing it.According to FIG. 2, three radial supporting walls 15 are spread overthe periphery between inner wall 14 and sealing lip 13. They extend nofarther than the sealing lip 13 in axial direction.

The following dimensions were chosen in this embodiment: the thicknessof the inner wall 14 and of the sealing lip 13 is roughly 0.5 mms, whilethe total diameter of the cup-seal non-return valve 1 is in themagnitude of 1 cm. The supporting walls 15 are approximately 1 mm thick,that means, roughly twice as thick as the sealing lip 13.

Owing to this dimensioning, sufficient rigidity is imparted to them inorder to stabilize the cup seal's shape, while nevertheless they aresoft enough to not inhibit the passage of pressure fluid. The entirecup-seal non-return valve 1 is of one-part design.

List of Reference Numerals

cup-seal non-return valve

pressure-reducing valve

inlet chamber

outlet chamber

control piston

bore

sleeve

front wall

tappet

valve closure member

valve seat

compression spring

sealing lip

inner wall

supporting walls

We claim:
 1. A cup-seal non-return valve for pressure-fluid-operatedpiston assemblies which is manufactured in one part of elastomericmaterial, comprising a cylindrical inner wall and a circumferentialsealing lip connected thereto which together form a profile of V-typeconfiguration, characterized in that a plurality of radial supportingwalls made of the same material are arranged between said inner wall andsaid sealing lip and are distanced from each other to permit saidsealing lip to move towards said inner wall when a sufficient pressureof pressure fluid is applied to a closed end of said V-typeconfiguration.
 2. A cup-seal non-return valve as claimed in claim 1,characterized in that three supporting walls are arranged between saidinner wall and said sealing.
 3. A cup-seal non-return valve as claimedin claim 2, characterized in that the supporting walls each are one anda half to three times as thick as the sealing lip.
 4. A cup-sealnon-return valve as claimed in claim 3, characterized in that thecylindrical inner wall at an open end of the V-profile projects beyondthe sealing lip and the supporting walls.
 5. A cup-seal non-return valveas claimed in claim 2, characterized in that the cylindrical inner wallat an open end of the V-profile projects beyond the sealing lip and thesupporting walls.
 6. A cup-seal non-return valve as claimed in claim 1,characterized in that the cylindrical inner wall at an open end of theV-profile projects beyond the sealing lip and the supporting walls.
 7. Acup-seal non-return valve as claimed in claim 1 characterized in that itis used in a pressure-reducing valve.
 8. A cup-seal non-return valve forpressure-fluid operated piston assemblies comprising:a cylindrical innerwall having first and second ends; a sealing lip angularly connected tosaid cylindrical inner wall at said first end of said cylindrical innerwall to form a V-shape with said cylindrical inner wall; and a pluralityof supporting walls arranged between said cylindrical inner wall andsaid sealing lip and distanced from each other to permit said sealinglip to move towards said cylindrical inner wall when a sufficientpressure of pressure fluid is applied to the outside surface of saidsealing lip.
 9. A cup-seal non-return valve as recited in claim 8wherein three supporting walls are arranged between said cylindricalinner wall and said sealing lip.
 10. A cup-seal non-return valve asrecited in claim 9 wherein said cup-seal non-return valve is included ina pressure reducing valve.
 11. A cup-seal non-return valve as recited inclaim 9 wherein said supporting walls each are one and a half to threetimes as thick as said sealing lip.
 12. A cup-seal non-return valve asrecited in claim 11 wherein said second end of said cylindrical innerwall extends beyond said sealing lip and said supporting walls.
 13. Acup-seal non-return valve as recited in claim 9 wherein said second endof said cylindrical inner wall extends beyond said sealing lip and saidsupporting walls.
 14. A cup-seal non-return valve as recited in claim 8wherein said supporting walls each are one and a half to three times asthick as said sealing lip.
 15. A cup-seal non-return valve as recited inclaim 14 wherein said second end of said cylindrical inner wall extendsbeyond said sealing lip and said supporting walls.
 16. A cup-sealnon-return valve as recited in claim 8 wherein said cup-seal non-returnvalve is included in a pressure reducing valve.
 17. A cup-sealnon-return valve as recited in claim 8 wherein said second end of saidcylindrical inner wall extends beyond said sealing lip and saidsupporting walls.
 18. A cup-seal non-return valve as recited in claim 8wherein said cylindrical inner wall, said sealing lip and saidsupporting walls are comprised of an elastomeric material.
 19. Apressure reducing valve comprising:a housing having a cylindrical bore;a control piston movable along said cylindrical bore of said housing andhaving:(a) a head with clearance from said cylindrical bore definingfirst and second chambers in said cylindrical bore, and (b) a body; avalve, responsive to movement of said control piston, for controllingfluid flow between said first and said second chambers; and a cup-sealnon-return valve disposed between said piston body and said cylindricalbore and having:(a) a cylindrical inner wall positioned against saidpiston body and having first and second ends, (b) a sealing lipangularly connected to said cylindrical inner wall at said first end ofsaid cylindrical inner wall to form a V-shape with said cylindricalinner wall and bearing against said cylindrical bore, and (c) aplurality of supporting walls arranged between said cylindrical innerwall and said sealing lip and distanced from each other to permit saidsealing lip to move towards said cylindrical inner wall when asufficient pressure of pressure fluid is applied to the outside surfaceof said sealing lip.
 20. A pressure reducing valve as recited in claim19 wherein three supporting walls are arranged between said cylindricalinner wall and said sealing lip of said cup-seal non-return valve.
 21. Apressure reducing valve as recited in claim 20 wherein said supportingwalls of said cup-seal non-return valve each are one and a half to threetimes as thick as said sealing lip.